If you wants to do enter an invoice on rent paid with GST 18%,you can follow given steps:
Step 1:Go to the Administration menu,
Step 2:Click on Masters,
Step 3:Click on Account,here you can create an account as Rent Paid,and select group Expense(Indirect/Admn.),save this master.
Step 4:Click on item,here you can also add and item as Rent Paid,mention Tax category as GST 18%,then there is an option in the bottom, sepcify purchase Account,Tag here Rent Paid Account and save this master.
Step 5:Now go to the transaction menu,
Step 6:Click Purchase,then click add,Please enter the voucher here,select the rent paid item,then enter all the information along with the voucher and save.